It is known to use both analog-style and digital-style instrumentation display devices to show the value of a sensed or measured parameter, e.g., time, speed, RPMs, temperature, pressure, fuel level, altitude, etc. Digital-style instrumentation display devices show the value of the sensed/measured parameter directly, i.e., by displaying a single discrete number that corresponds to the current value of the parameter. In contrast, analog-style instrumentation display devices show the value of the sensed/measured parameter indirectly, i.e., by moving a pointer, needle or other indicator (collectively “pointer”) within a predetermined range of motion (also known as a scale) that corresponds to the upper and lower measurement limits. The position of the pointer within the scale indicates the relative value of the sensed parameter (i.e., relative to the full scale). In some cases, indicia are provided to indicate numerical values for different positions on the scale, while in other cases only relative information such as “HOT” and “COLD” are provided.
It will be appreciated that the style (i.e., either analog or digital) of the display device is independent of the technology used for sensing/measuring the parameter and the technology used to operate the display. For example, a temperature gauge having a display dial with a moving pointer is considered to have an analog-style display, even if a digital sensing device is used to sense the temperature and a microprocessor-driven digital stepper motor is used to move the pointer. Further, even if the display device itself is fully digital, e.g., a computer-driven flat-panel display, it may still constitute an analog-style display device if it uses the image of a moving pointer traveling within a scale to convey sensed/measured parameter information to the viewer.
For reasons not fully understood, is believed that users can more quickly obtain useful information from analog-style instrumentation displays than from digital-style information displays. This appears especially true concentration-intensive activities such as driving or piloting a vehicle. In addition, many users simply prefer analog-style instrumentation displays for aesthetic reasons. Thus, analog-style instrumentation displays may be used in vehicles that extensively used digital technology for parameter sensing/measurement and communication.
It is known to provide a “redline” or similar color-coded indicia on the scale of an analog-style instrumentation display to denote the portion of the scale having values that are outside normal operating values. When the pointer of a display moves beyond the redline, it is important for the operator (e.g., of a vehicle) to take notice as soon as possible so as to assess whether corrective action is required. However, when numerous analog-style instrumentation displays are used together, it may become difficult to rapidly assess if any parameter is outside of its nominal operating range, even with the use of redlines or color-coded scales. A need therefore exists, for analog-style instrumentation displays that convey additional information to the user regarding the sensed parameter.